Manufacture of rubber solfs



Mar. 6, 1923. 1,447,239 6. FERGUSON MANUFACTURE OF RUBBER SOLES Filed June 24, 1920 Patented Mar. 6, 1923.

UNETE ST earner FF GEORGE FERGUSON, 0F WOLLASTON, MASSACHUSETTS, ASSIGNOR TO UNITED SHOE MACHINERY CORPORATION, OF PATERSON, NEW JERSEY, A CORPORATION OF NEW JERSEY.

MANUFACTURE OF RUBBER SOLES.

Application filed June 24, 1920. Serial No. 391,467.

To all whom it may concern:

Be it known that I, Gronon FERGUSON, a citizen of the United States, and resident of lrvollaston, in the county of Norfolk and State of Massachusetts, have invented certain Improvements in the Manufacture of Rubber Soles, of which the following description, in connection with the accompanying drawings, is a specification, like reference characters on the drawings indicating like parts in the several figures.

This invention relates to the manufacture of soles for boots and shoes and is herein described in connection with the manufacture of a so-called rubber sole for a turned shoe.

Such soles are commonly made by superposing upon a blank of rubber or rubberized material, a strengthening blank, which is usually friction fabric, placing the composite blank in a suitable mold and subjecting it to heat and pressure. The mold is so shaped as to produce a sewing rib spaced from the margin of the sole, the outer wall of which is perpendicular, to form the usual sewing shoulder and the inner wall of which is undercut and spaced from the raised middle portion of the sole by a groove or gutter. The purpose of forming an undercut inner wall on the rib is to facilitate the sewing operation. During the sewing operation the channel guide of the sewing machine runs in the base of the channel beneath the overhanging wall of the rib thus aiding the operator in holding the shoe firmly up to the machine and thereby facilitating the production of a tight seam. In the manufacture of leather soles for turn shoes, the inside channel is an inclined slit made by means of a knife set at the proper angle, the sole beingsubstantially flat on top and having no gutter. The form of the leather sole is preferable to that of the rubber one, because the lip engages the channel guide of the sewing machine more firmly and because there is no groove or gutter which must later be filled or bridged in some way before the shoe in which the sole is incorporated is completed. It is not practicable, however, to use a knife to form the inside channel and lip of a rubber sole since such a procedure results in the severing of the strengthening fabric and thereby in weakening the substance through which the stitches pass.

According to the present invention a sole of vulcanized material may be made which has substantially the same form as a leather sole and in which no severing of the strengthening fabric occurs. In order to produce this result,'a strip of friction fabric or other lip-forming material is laid around the margin of the sole blank, a material, for example powdered chalk, which is capable of preventing vulcanization, is inserted beneath the inner margin of the strip, and then the composite blank is subjected to heat and pressure. The powdered chalk, or similarly acting material, prevents the inner margin of the strip from being vulcanized to the body of the sole so that when the vulcanizing of the sole has been completed, this free inner margin of the strip forms a lip, and beneath it is a channel, the lip and channel being similar in form to those of a leather sole.

Referring now to the accompanying drawmgs,

Fig. 1 is a perspective of a completed sole made in accordance with the present invention, and

Fig. 2 is a cross-section on the dot-anddash line of Fig. 1.

The illustrative sole is designed for use in the manufacture of a shoe having a wooden heel and consequently a nailed heel seat. In such a sole the line of stitches extends only part away around the sole, the sewing shoulder terminating as shown at about the heel breast line; but it should be understood that the present invention is equally well adapted to the manufacture of a sole in which the sewing shoulder extends entirely around the sole and the heel seat is of the sewed type.

In the manufacture of the sole shown in the drawings, a blank of rubber or rubberized material 3, hereinafter referred to for convenience as rubber, is died out. Commonly this blank is made entirely of uncured rubber but in any event it contains a large proportion of vulcanizable material. A blank of friction fabric 5, hereinafter referred to as the strengthening blank, is also died out, the outline of thestrengthening blank being similar to but a little smaller than that of the sole blank beginning at blank will extend practically the full length of the sole. The strengthening blank 5 is next laid upon the rubber blank, its edge be ingspaced slightly from that of the rubber blank. A strip of friction fabric 7 hereinafter referred to as the lip-forming strip. is then laid around the margin of the partly assembled composite blank, its outer edge registering with the outer edge of the strengthening blank. Beneath the 1nner margin or portion of the lip-forming strip is placed a material such as powdered chalk or paper which is capable of preventing vulcanization. It should be understood that the friction fabric of which the strengthening blank and the lip-forming blank are made possesses strong adhesive qualities so that the strengtheningblank adheres firmly to the rubber blank and the outer margin of the lip-forming blank which has no powdered chalk beneath it adheres similarly to the strengthening blank.

The completely assembled composite blank is then placed in a suitable mold and subjected to heat and pressure so as to mold it to the form shown and to vulcanize it. In this molding operation there is formed in the illustrated sole a shallow groove or gutter 9 of small cross-section since this facili tates the proper sewing of the sole to the upper of the shoe; but this gutter is of such small dimensions that it requires no subsequent filling, the completed sole having practically the form of a leather sole in which the lip is formed by a cutting operation. After the finished sole has been removed from the vulcanizing mold it will have a lip 17 which is the free unvulcanized inner margin or portion of the lip-forming strip 7. If the powdered chalk or other similarly acting material has not been accurately laced, the width of the lip 17 may vary at ifferent localities; and in order to make it of uniform width, if it is not, the end of a screw-driver or similar tool may be run around in the channel beneath the lip 17 This treatment is entirely feasible since the molding and vulcanizing operation has produced the sewing rib 11 which limits the extent to which the screw-driver or other tool may be inserted underneath the lip 17 and thereby ensures that the lip shall be of uniform width throughout.

Although the method of obtaining a lip of uniform width which has been described above has been found satisfactory with the particular sole shown in which a rib is formed during the molding operation, it is obviously possible to secure the same result in other ways, whether or not the finished sole has a rib. For example, the lip-forming strip may be attached to the strengthening blank by a properly located line of fasteners of any suitable type, such line determining the location of the base of the lip,

or a paper pattern of proper form may be laid on the strengthening blank and then the lip-forming strip applied with its inner margin extending over the margin of the pattern. In short, any Suitable procedure by which the outer margin of the lip-forming strip may be prepared for vulcanizing to the sole while the inner margin is prevented from being so vulcanized may be used.

Although the invention has been described as being practiced by laying the fabric strengthening blank on the rubber blank and then laying the fabric lip-forming strip on the strengthening blank, it should be understood that the particular order in which the steps are carried out is not essential and that, if materials of sufficient strength are used, the strengthening blank may be omitted. It should also be understood that, although the illustrated sole is provided with a shoulder and is designed for so-called single-faced stitches which pass through the base of the shoulder. the particular shape oi the margin of the sole may be varied to proride for stitching of other types; and that the word sole as used in the claims is in tended'to cover broadly outsoles and insoles.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. The method of producing a molded and vulcanized sole having a lip attached thereto which comprises placing around the margin of a solea blank of vulcanizable material a strip of lip-forming material, inserting beneath the inner portion of the strip, material capable of preventing vulcanization of that portion of the strip, and then vulcanizing the article thus assembled.

2. The method of producing a molded and vulcanized sole having a lip attached thereto which comprises placing around the margin of a sole blank of vulcanizable material a strip of lip-forming material, attaching the lip-forming strip to the sole by fastening means spaced from the inner edge of the strip, inserting beneath the inner portion of the strip, material capable of preventing vulcanization of that port-ion of the strip, and then vulcanizing the article thus assembled.

3. The method of making a molded sole having a lip attached thereto which comprises placing upon a blank of vulcanizable material a composite blank of strengthening material, the composite blank comprising a body portion and a strip .laid around the margin of the body portion and having its inner margin separated from the body portion by non-vulcanizab-le material, and then molding and vulcanizing the assembled blanks. I

4. The method of making a molded and vulcanized sole which comprises superposing upon a blank of Vulcanizable material a strengthening blank and a lip-forming blank, inserting between the inner portion of the lip-forming blank and the strengthening blank, a material which Will prevent said inner portion from being vulcanized to the strengthening blank, and then molding and vulcanizing the composite blank.

5. The method of making a molded and vulcanized sole which comprises superposing upon a blank of vulcanizable material a strengthening blank and a lip-forming blank, the two last-named blanks being attached to each other by fastening means spaced from the inner edge of the lip-forming blank, inserting between the inner portion of the lip-forming blank and the strengthening blank a material which will prevent said inner portion from being vulcanized to the strengthening blank, and-then molding and vulcanizing the composite blank.

6. The method of making a molded and vulcanized sole which comprises providing a blank of vulcanizable material, a fabric blank and a fabric strip, laying the strip around the edge of the fabric blank and attaching its outer portion to the fabric blank, inserting beneath the free inner portion of the strip material capable of preventing the inner portion from being vulcanized to the fabric blank, laying the fabric blank with its attached strip upon the blank of vulcanizable material, and molding and vulcanizing the composite blank.

As an article of manufacture, a sole of vulcanized material having a lip, said lip consisting of the free inner margin of a strip of sheet material, the outer margin of which is vulcanized to the sole.

8. As an article of manufacture, a vulcanized sole having a lip, said lip consisting of the free inner margin of a strip of a material difi'erent from that of the body ofthe sole, the outer margin of the strip being vulcanized to the sole.

In testimony whereof I have signed my name to this specification.

GEORGE FERGUSON. 

